WARSAW, Jan 18 (Reuters) - Polish electricity demand hit a record of more than 27 gigawatts (GW) on Monday, but the grid operator PSE said the system could cope with the surge in usage caused by freezing temperatures.

The previous record was 26.8 GW, set on Dec. 10.

Poland, which generates electricity mostly from ageing coal-fuelled power stations, has in the past faced power shortages during surges in demand. PSE said power stations had been working at full capacity.

This cold snap has lasted three days, but forecasts say it will ease this week. The temperature in Warsaw was minus 18 Celsius on Monday morning.

"The record high levels have been exceeded. We have been prepared for that, the system works in a stable way, the reserve level is sufficient at this stage," a PSE spokeswoman said, adding demand could rise above 27 GW on Monday.

(Reporting by Anna Koper; Writing by Agnieszka Barteczko; Editing by Edmund Blair)